Interfacial Fracture Mechanics of Metal Matrix Nanocomposites

Abstract

Metal matrix nanocomposites reinforced with nanoparticles such as carbon nanotubes, graphene nanoplatelets, and ceramic nanoparticles, offer exceptional mechanical, thermal, and fracture properties for structural applications. The interfacial region between the metal matrix and nanofillers plays a critical role in controlling fracture behavior, including crack initiation, propagation, and energy dissipation. This study investigates interfacial fracture mechanics in MMNCs, focusing on the role of nanofiller dispersion, functionalization, and interfacial bonding. Aluminum and titanium matrices were reinforced with CNTs, GNPs, and SiC nanoparticles, fabricated via powder metallurgy and stir-casting methods. Interfacial strength, fracture toughness, and crack propagation were assessed using micro-cantilever bending, micro-pillar fracture, and compact tension tests. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), and focused ion beam (FIB) techniques were used to examine the fracture surface and interfacial debonding. Cohesive zone modeling and finite element analysis (FEA) quantified stress distribution and interfacial energy release rates. Results show that strong interfacial bonding and uniform nanoparticle distribution significantly increase fracture toughness, reduce crack propagation, and promote energy absorption mechanisms such as particle pull-out, crack deflection, and plastic deformation in the metal matrix. These findings provide insight into designing MMNCs with superior interfacial fracture resistance for aerospace, automotive, and defense applications.